The feature of establishing a prescribed relationship (e.g., one of authentication) and exchanging various kinds of information by various methods between smartphones or other such terminal devices provided with a display unit, such as a liquid crystal display, and with a touch panel arranged covering the display unit, is known in the prior art.
For example, Patent Reference 1 discloses a feature whereby a server device mediates a process for generating relationship information between terminal devices (authentication). Specifically, the server device, upon receiving an authentication request for another user from a terminal device (a friend registration request), references a prescribed database, and searches for the user to be registered as a friend. An invitation is then sent to the terminal device of this target user, and a process prompting the user to join a prescribed service is carried out. Then, once the user in question joins the service, authentication is established for the first time, and the user is registered as a friend.